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no reproduction of any part may take place without the written permission of Cambridge University Press.

First published 2010

Printed in the United Kingdom at the University Press, Cambridge

A catalog record for this publication is available from the British Library

Additional resources for this publication at www.cambridge.org/9780521518031

Cambridge University Press has no responsibility for the persistence or accuracy of URLs for external or third-party internet
websites referred to in this publication, and does not guarantee that any content on such websites is, or will remain, accurate
or appropriate.

Every effort has been made in preparing this book to provide accurate and up-to-date information, which is in accord with
accepted standards and practice at the time of publication. Although case histories are drawn from actual cases, every effort
has been made to disguise the identities of the individuals involved. Nevertheless, the authors, editors, and publishers can
make no warranties that the information contained herein is totally free from error, not least because clinical standards
are constantly changing through research and regulation. The authors, editors, and publishers therefore disclaim all liability
for direct or consequential damages resulting from the use of material contained in this book. Readers are strongly advised
to pay careful attention to information provided by the manufacturer of any drugs or equipment that they plan to use.

This book is dedicated to God in whom all is possible; the love and support of my parents; the humor and inspiration of my
sons Nadeem and Corey; the encouragement of my darling Bruce; and the tolerance of Jordan my Great Dane who missed many long
walks while I spent time writing this book.

Gloria Galloway

Contents

Preface

ix

Acknowledgments

x

1 Introduction, history, and staffing for intraoperative monitoring

Marc R. Nuwer

1

2 The preoperative assessment

Gloria M. Galloway

10

3 Magnetic stimulation

Khaled M. Zamel

19

4 The operating-room environment and team approach: pitfalls and technical factors

Khaled M. Zamel

33

5 Basic pharmacology of anesthetic agents and their effects on neurophysiological monitoring

16 Interpreting and reporting the neurophysiologic data to the surgical team: how to do it and when it is indicated

Jaime R. López

207

17 Intraoperative wake-up test

Marc R. Nuwer

221

18 Postoperative studies and outcomes: clinical indications and usefulness of a postoperative study

Gloria M. Galloway

225

Index

236

Preface

Since its inception clinically in the late 1970s and early 1980s, intraoperative neurophysiologic monitoring has shown a steady
increase in use for surgeries in which neural structures may be at risk of injury. The types of and varieties of neurophysiologic
techniques available for multimodality monitoring have allowed a patient-centered individualized approach to the practice
and planning of these surgical cases. Some neurophysiologic techniques may carry inherent risks. An example of this is the
potential risk of induction of seizures with the use of direct cortical and transcranial electric motor stimulation. Other
risks involve inadvertent motor movements, tongue and lip lacerations. In addition, the more widespread use of multimodality
intraoperative neurophysiologic techniques has allowed surgeons to become somewhat more aggressive and expansive in their
surgical approaches. An example of this is the ability to be more expansive during resection of an intramedullary spinal tumor
when motor, sensory, and possibly electromyography monitoring indicate that no change in electrophysiologic signals from these
pathways has occurred.

The risk of consequential harm as a result of a neurophysiologic technique coupled with the increased ability to be more expansive
surgically has changed methods of neurophysiologic monitoring and allowed the field to make an impact on patient safety and
quality of care during surgical procedures. Therefore, it is especially important that those performing and interpreting these
studies be adequately trained. This has been challenging given the relatively small number of training programs in the field:
furthermore, several organizations whose members practice intraoperative neurophysiology have been led to develop guidelines,
training courses, and additional certification programs specially geared toward this increasing subspecialty. Fellowship training
programs have been around for many years in general neurophysiology as well as subspecialty areas such as epilepsy, including
surgical epilepsy and electromyography (EMG). Often interest in intraoperative neurophysiology begins through subspecialty
fellowships in EEG, epilepsy, or EMG. Several years ago a separately defined neurologic fellowship track was developed in
intraoperative neurophysiology, similar to the tracks that already exist in EEG and EMG.

This book is a compilation of the current trends in intraoperative neurophysiology with chapters on various modalities and
clinical uses. Separate chapters devoted to anesthesia, operating-room environment, special considerations in pediatrics and
the interpretation and reporting of neurophysiologic data are useful and complementary. This book can be helpful to trainees
as well as neurophysiologists already in practice but interested in other approaches to familiar techniques or in reviewing
new techniques outside of their typical practice pattern. Questions on the topics covered in the chapters with detailed answers
serve as a nice supplement on the accompanying website (www.cambridge.org/9780521518031). In some chapters, illustrative case examples are also included.

Physicians, PhD neurophysiologists, technicians, fellows, and residents can use this book for self-review and preparation
and, through improved quality techniques and interpretation, may positively impact patient care.

Gloria Galloway

Acknowledgments

Enormous thanks to Ed Buggie, our neurophysiology laboratory manager, who always supported the need for improved equipment
and enhanced training. Our excellent neurophysiologic technologists, Sharon Newell, Judy Brown, Christina Castleberry, and
David Brooks, provided excellent technical expertise, were not afraid to give their opinions, and always provided much needed
humor and silliness to balance out difficult situations. Much gratitude is given to our orthopedic and neurosurgical colleagues;
E. Steve Roach and the neurology division for the support of our neurophysiologic endeavors as we grew together to improve
patient care. Lastly, we owe enormous gratitude to those patients who entrusted their care to us.